Vinylpyrrolidone and vinylimidazole copolymers, their preparation and their use in detergents

ABSTRACT

Copolymers which are obtainable by free radical copolymerization of a mixture of 
     (a) from 20 to 95% by weight of 1-vinylpyrrolidone, a 1-vinylimidazole or a mixture of 1-vinylpyrrolidone and/or 1-vinylimidazoles which may contain up to 20% by weight of other monoethylenically unsaturated monomers and 
     (b) from 5 to 80% by weight of water-insoluble polymers which contain at least one ethylenically unsaturated double bond and/or one mercapto group in the molecule, processes for the preparation of the copolymers by copolymerization of the compounds of groups (a) and (b) in the abovementioned amounts in water, an alcohol, an ester or a ketone in the presence of free radical initiators, and the use of the copolymers thus obtainable and of copolymers of from 20 to 95% by weight of 1-vinylpyrrolidone or a mixture of 1-vinylpyrrolidone with up to 20% by weight of other monoethylenically unsaturated monomers and 
     from 10 to 80% by weight of styrene as additives for detergents for inhibiting the dye transfer during the wash process, and detergents which contain the stated copolymers.

The present invention relates to copolymers of 1-vinylpyrrolidone and1-vinylimidazoles which can be prepared in the presence ofwater-insoluble polymers which contain at least one ethylenicallyunsaturated double bond and/or one mercapto group in the molecule, aprocess for the preparation of the copolymers by copolymerization of1-vinylpyrrolidone and 1-vinylimidazoles in the presence ofwater-insoluble polymers which contain at least one ethylenicallyunsaturated double bond and/or one mercapto group in the molecule, insolvents, in the presence of free radical initiators, and the use of thecopolymers which can be prepared in this manner and the copolymers of1-vinylpyrrolidone and styrene as additives for detergents forinhibiting dye transfer during the wash process, and detergents whichcontain the stated copolymers.

DE-B-22 32 353 discloses detergent and cleaning agent mixtures whichessentially consist of from 95 to 60% by weight of nonionic detergentsand from 5 to 40% by weight of a partially or completely water-solublepolyvinylpyrrolidone and are essentially free of anionic surfactants.The polymers of vinylpyrrolidone prevent dye transfer from colored towhite textiles during the wash process. The polymers of vinylpyrrolidonehave molecular weights of from about 10,000 to about 1,000,000. Bothhomopolymers and copolymers of vinylpyrrolidone are suitable. Examplesof useful comonomers are acrylonitrile or maleic anhydride. However, theefficiency of the vinylpyrrolidone polymers as dye transfer inhibitorsis very adversely affected by anionic surfactants.

DE-A-28 14 287 discloses detergents and cleaning agents which containanionic and/or nonionic surfactants, builders and other conventionaldetergent additives and, as discoloration-inhibiting additives, from 0.1to 10% by weight of water-soluble or water-dispersible homo- orcopolymers of N-vinylimidazole. The polymers have a specific viscosityof from 0.01 to 5 in 1% strength by weight aqueous solution at 20° C.

The abovementioned polymers have the disadvantage that they are neitherbiodegradable nor removable from the wastewater by adsorption on sewagesludge.

The object of the present invention is to provide novel substances and aprocess for the preparation of the novel substances. It is a furtherobject of the present invention to provide a detergent additive whichprevents dye transfer during the wash process and which can beeliminated from the wastewater at least partially by adsorption on thesewage sludge.

We have found that these objects are achieved by the copolymers whichare obtainable by free radical copolymerization of a mixture of

(a) from 20 to 95% by weight of 1-vinylpyrrolidone, a

1-vinylimidazole of the formula (I) ##STR1## where R is H, CH₃ or C₂ H₅and n is from 1 to 3, a mixture of such 1-vinylimidazoles or a mixtureof 1-vinylpyrrolidone and/or 1-vinylimidazoles of the formula I whichcontain up to 20% by weight of other monoethylenically unsaturatedmonomers, and

(b) from 5 to 80% by weight of water-insoluble polymers which contain atleast one ethylenically unsaturated double bond and/or one mercaptogroup in the molecule.

The present invention furthermore relates to a process for thepreparation of copolymers, wherein

(a) a 1-vinylpyrrolidone, a 1-vinylimidazole of the formula I, a mixturethereof or a mixture of 1-vinylpyrrolidone and/or 1-vinylimidazoleswhich contain up to 20% by weight of other monoethylenically unsaturatedmonomers, and

(b) from 5 to 80% by weight of water-insoluble polymers which contain atleast one ethylenically unsaturated double bond and/or one mercaptogroup in the molecule

are polymerized in water, an alcohol, an ester or a ketone, each havinga boiling point below 135° C., or a mixture of the stated solvents, inthe presence of free radical initiators and in the presence or absenceof protective colloids and surfactants.

The last-mentioned object is achieved, according to the invention, bythe use of the abovementioned copolymers and by the use of copolymers of

(a) from 20 to 95% by weight of 1-vinylpyrrolidone or a mixture of1-vinylpyrrolidone with up to 20% by weight of other monoethylenicallyunsaturated monomers and

(b) from 5 to 80% by weight of styrene as an additive for detergents forinhibiting dye transfer during the wash process and with detergentsbased on surfactants and, if required, builders and other conventionalcomponents, if the detergents contain from 0.1 to 10% by weight of anovel copolymer or of a copolymer of

(a) from 20 to 95% by weight of 1-vinylpyrrolidone or a mixture of1-vinylpyrrolidone with up to 20% by weight of other monoethylenicallyunsaturated monomers and

(b) from 5 to 80% by weight of styrene.

Monomers of group (a) are 1-vinylpyrrolidone and 1-vinylimidazoles ofthe formula (I) ##STR2## where R is H, CH₃ or C₂ H₅ and n is from 1 to3.

R may be in the 2-, 4- and 5-position of the imidazole ring, if R ismethyl or ethyl, these groups may replace the 3 substitutable hydrogenatoms on the imidazole ring in the 2-, 4- and 5-position. Examples ofsuitable compounds are 1-vinylimidazole, 1-vinyl-2-methylimidazole,1-vinyl-2,4 -dimethylimidazole, 1-vinyl-2,4,5-trimethylimidazole,1-vinyl-2-ethylimidazole, 1-vinyl-4,5-diethylimidazole and1-vinyl-2,4,5-triethylimidazole. Mixtures of the stated monomers in anyratio can also be used, for example mixtures of 1-vinylpyrrolidone and1-vinylimidazole or mixtures of 1-vinylimidazole and1-vinyl-2-methylimidazole.

The monomers of group (a) can be used in the copolymerization eitheralone or as a mixture with one another and with up to 20% by weight ofother monoethylenically unsaturated monomers. These are preferablymonomers which contain a basic nitrogen atom, either in the form of freebases or in quaternized form, and monomers which have an amido groupwhich may be substituted. Examples of suitable monomers of this type areN, N'-dialkylaminoalkyl (meth)acrylates, eg. dimethylaminoethylacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl acrylate,diethylaminoethyl methacrylate, dimethylaminopropyl acrylate,dimethylaminopropyl methacrylate, diethylaminopropyl acrylate,diethylaminopropyl methacrylate, dimethylaminobutyl acrylate,dimethylaminobutyl methacrylate, dimethylaminoneopentyl acrylate anddimethylaminoneopentyl methacrylate. Further suitable basic monomers ofthis group are N, N'-dialkylaminoalkyl(meth)acrylamides, eg. N, N'-di C₁-C₃ -alkylamino-C₂ -C₆ -alkyl(meth)acrylamides, such asdimethylaminoethylacrylamide, dimethylaminoethylmethacrylamide,diethylaminoethylacrylamide, diethylaminoethylmethacrylamide,dipropylaminoethylacrylamide, dipropylaminoethylmethacrylamide,dimethylaminopropylacrylamide, dimethylaminopropylmethacrylamide,diethylaminopropylacrylamide, diethylaminopropylmethacrylamide,dimethylaminoneopentylacrylamide, dimethylaminoneopentylmethacrylamideand dialkylaminobutylacrylamide. Further suitable monomers of this groupare 4-vinylpyridine, 2-vinylpyridine and/or diallyl(di)alkylamines inwhich the alkyl group is of 1 to 12 carbon atoms. The abovementionedbasic monomers are used in the copolymerization in the form of the freebases or of the salts with organic or inorganic acids or in quaternizedform. For example, carboxylic acids of 1 to 7 carbon atoms, eg. formicacid, acetic acid or propionic acid, benzenesulfonic acid,p-toluenesulfonic acid or inorganic acids, such as hydrohalic acids, forexample hydrochloric acid or hydrobromic acid, are suitable for saltformation. The basic monomers stated above by way of example may also beused in quaternized form. For example, alkyl halides where the alkylgroup is of 1 to 18 carbon atoms, eg. methyl chloride, methyl bromide,methyl iodide, ethyl chloride, propyl chloride, hexyl chloride, dodecylchloride, lauryl chloride and benzyl halide, in particular benzylchloride and benzyl bromide, are suitable for quaternization. Thequaternization of the nitrogen-containing basic monomers can also becarried out by reacting these compounds with dialkyl sulfates, inparticular diethyl sulfate or dimethyl sulfate. Examples of quaternizedmonomers of this group are trimethylammoniumethyl methacrylate chloride,dimethylethylammoniumethyl methacrylate ethylsulfate anddimethylethylammoniumethylmethacrylamide ethylsulfate. Further suitablemonomers are 1-vinylimidazolium compounds of the formula ##STR3## whereR is H, C₁ -C₁₈ -alkyl or benzyl and X⊖ is an anion.

The anion may be a halogen ion or a radical of an inorganic or organicacid. Examples of quaternized 1-vinylimidazole of the formula I are3-methyl-1-vinylimidazolium chloride, 3-benzyl-1-vinylimidazoliumchloride, 3-n-dodecyl-1-vinylimidazolium bromide and3-n-octadecyl-1-vinylimidazolium chloride.

If the abovementioned monomers are used together with vinylpyrrolidoneor the vinylimidazoles, they are present in the mixture preferably in anamount of 1 to 18% by weight. The monomers of group (a) are used in thecopolymerization in amounts of from 20 to 95, preferably from 30 to 90,% by weight.

Suitable components (b) which are used in the polymerization batch in anamount of from 5 to 80, preferably from 10 to 70, % by weight arewater-insoluble polymers which contain at least one ethylenicallyunsaturated double bond and/or one mercapto group in the molecule. Theaverage molecular weight M_(w) of the water-insoluble polymers is, forexample, at least 500, preferably from 800 to 200,000. The averagemolecular weight of some polymers of component (b) is above the statedrange and cannot be definitively determined. This applies, for example,to the polybutadienes, some of which contain crosslinked structures.

The polymers (b) are water-insoluble. Water-insoluble is to beunderstood in this context as meaning a polymer which has a solubilityof not more than 0.1% by weight in water.

The suitable polymers may have a vinyloxy, vinyl, allyl, acryloyl,methacryloyl, phenylvinyl or isopropenylphenyl unit as a terminal group.They may have different chemical structures and may be polycondensates,polyadducts or polymers, for example polyesters, polyamides,polytetrahydrofurans, polysiloxanes, epoxy resins, polyurethanes,polystyrenes, polyacrylates or polyisobutenes. Polymers (b) of this typeare generally referred to in the literature as macromonomers. Suchcompounds are described in, for example, P. F. Rempp and E. Frank, Adv.Polym. Sci. 58 (1984), 1-53, or Y. Kawakami in Encycl. Polym. Sci.Engng. 9, 195-204, John Wiley: New York 1987. The polymers may alsocontain more than one of the vinyl terminal groups described. They arethen often referred to as polymeric crosslinking agents. Other suitablepolymers of group (b) are compounds which contain at least one C--Cdouble bond in the main chain, for example polybutadienes or unsaturatedpolyesters.

The preparation of the polymers (b) is known to the skilled worker. Forexample, the compounds referred to as macromonomers can be obtained byinitiating or terminating, by means of a vinyl-carrying reagent, areaction synthesizing the polymer, the vinyl groups being incorporatedin the polymer. For example, living anionic polymers of styrene or alkyl(meth)acrylates with allyl halides, p-chloromethylstyrene,(meth)acryloyl chloride, glycidyl methacrylate, 1-isopropenyl-3-[2-(methyl-2-isocyanato) ethyl]benzene or methacryloyl isocyanate can bereacted to give corresponding macromonomers. Correspondingly,hexamethylcyclotrisiloxane or octamethylcyclotetrasiloxane can besubjected to anionic polymerization with alkali metal alcoholates andthen reacted with reactive methacrylic derivatives to givemethacryloyl-terminated polydimethylsiloxanes. Another method which ispossible in principle is to prepare a prepolymer having a definedterminal group by using suitable initiators, chain transfer agents orterminating reagents. The terminal group of the prepolymer is thenreacted in a second stage with a vinyl-carrying compound, the vinylgroup being retained. Polymerizations in the presence of thioglycolicacid lead, for example, to carboxyl-carrying polymers, which can then beesterified with hydroxyethyl methacrylate to give a macromonomer.Condensation and addition reactions likewise frequently lead to suitableprepolymers which have a defined content of reactive groups. Polymericcrosslinking agents can be obtained in a similar manner to thesecompounds which are referred to as macromonomers. Most frequently, a bi-or monofunctional polymer is reacted with a suitable vinyl compound forthis purpose. For example, polymeric diols and diamines can be convertedinto the corresponding (meth)acrylates or (meth)acrylamides by means ofa (meth)acrylic compound. Polydimethylsiloxanes can be obtained, forexample, by a corresponding reaction through terminal OH groups and canthen be converted into the corresponding methacrylates.

Other suitable polymers of group (b) are polycondensates or polyadductswhich are prepared partially from ethylenically unsaturated buildingblocks and in which at least one double bond is retained in the polymer.Examples of such polymers are polyesters or polyamides, each of whichhave been obtained with the partial use of monoethylenically unsaturateddicarboxylic acids, such as maleic acid, itaconic acid or fumaric acid.Further suitable unsaturated polyesters can also be obtained by thepartial use of an unsaturated diol, such as but-2-ene-1,4-diol. Suitablepolycondensates are also obtainable by the partial use of unsaturatedcarboxylates and carboxamides in the reaction with saturatedcarboxylates, lactones, carboxamides and lactams. Examples of suchcompounds are copolyesters with ricinoleic acid. The preparation of thepolyesters and polyamides is known to the skilled worker. They areobtainable, for example, by cocondensation of saturated dicarboxylicacids, such as aliphatic dicarboxylic acids having 2 to 12 carbon atomsin the molecule, for example succinic acid and adipic acid, and aromaticdicarboxylic acids, such as phthalic acid, isophthalic acid andterephthalic acid, with unsaturated dicarboxylic acids, such as maleicacid, fumaric acid or itaconic acid, and diols, such as aliphatic diols,for example ethylene glycol, propylene glycol, butanediol, hexanedioland neopentyldiglycol, polyethylene glycols, polytetrahydrofurans andaromatic diols, such as di(hydroxyphenyl)dimethylmethane anddihydroxydiphenyl sulfone, or diamines, such as aliphatic diamines, forexample ethylenediamine or propylenediamine, hexamethylenediamine and4,4'-diaminodicyclohexyldiamine, diamines of polyethylene glycol andaromatic diamines, such as p- and m-phenylenediamine. The dicarboxylicacids can be used both in this form and in the form of anhydrides oresters. Unsaturated polyesters which contain maleic acid, fumaric acid,itaconic acid or but-2-ene-1,4-diol groups are particularly preferred.Further suitable polymers of group (b) are homo- and copolymers ofisoprene, butadiene or norbornene. Homopolymers of butadiene orcopolymers which contain butadiene together with other comonomers, suchas styrene, acrylonitrile, acrylates of alcohols of 1 to 8 carbon atoms,such as ethyl acrylate, butyl acrylate and ethylhexyl acrylate,isoprene, vinyl ethers where the alkyl chain is of 1 to 18 carbon atomsand acrylic acid, as polymerized units are particularly preferred. Suchpolymers are obtainable by various ionic, metal-catalyzed or freeradical processes, for example polybutadiene oils by anionicpolymerization, or the styrene/butadiene copolymers often referred to assynthetic rubbers by polymerization in aqueous dispersion.

Suitable components (b) are also all water-insoluble polymers whichcontain at least one mercapto group in the molecule. The mercapto groupsor thiol groups may be present as terminal groups or in a side chain inthe polymer. The polymer itself may have different chemical structuresand comprise polycondensates, polyadducts or polymers. Examples aremercaptoalkyl-carrying polysiloxanes, for exampleco(dimethylsiloxy)[(mercaptopropyl)methylsiloxane]containing from 1 to10 mol % of mercaptopropyl(methyl)siloxy groups.

Further examples of compounds of component (b) arebis(thiol)polytetrahydrofurans or copolymers of monoethylenicallyunsaturated carboxylic acids which have been reacted with thioalkanols,such as mercaptoethanol, mercaptopropanol, mercaptobutanol, glyceryldithioglycolate, thiodiglycol, ethylthioethanol, dodecylthioethanol,ethoxylated alkylmercaptans and methylmercaptoethanol, orthioalkylamines, such as 2-amino-5-mercaptothiadiazole,aminomercaptoethane and aminomercaptopropane. The thioalkanols orthioalkanamines are present in either esterified or amidated form. Thecopolymers are derived, for example, from acrylic acid, methacrylicacid, maleic acid or itaconic acid. Suitable comonomers are styrene,1-alkenes of 4 to 30 carbon atoms, isobutene, vinylalkyl ethers of 1 to18 carbon atoms in the molecule and alkyl (meth)acrylates having 1 to 18carbon atoms in the molecule.

The novel copolymers are prepared by copolymerizing

(a) from 20 to 95% by weight of 1-vinylpyrrolidone, a 1-vinylimidazoleof the abovementioned formula I, a mixture thereof or a mixture of1-vinylpyrrolidone and/or 1-vinylimidazoles which contains up to 20% byweight of other monoethylenically unsaturated monomers and

(b) from 5 to 80% by weight of water-insoluble polymers which contain atleast one ethylenically unsaturated double bond and/or one mercaptogroup in the molecule,

in water, an alcohol, an ester or ketone, each having a boiling pointbelow 135° C, or a mixture of the stated solvents, in the presence offree radical initiators in the presence or absence of protectivecolloids and surfactants. The copolymerization of components (a) and (b)can be carried out by all methods of solution, emulsion or precipitationpolymerization. The concentration of components (a) and (b) in thestated solvents is not critical and is advantageously from 1 to 80,preferably from 20 to 60, % by weight. Examples of suitable solvents aremethanol, ethanol, isopropanol, n-propanol, n-butanol, isobutanol,tert-butanol, methyl acetate, ethyl acetate, isopropyl acetate, n-propylacetate, methyl propionate, ethyl propionate, methyl ethyl ketone,acetone and diethyl ketone. The alcohols, ketones and esters shouldpreferably have a boiling point below 135° C. The organic solvents aredistilled off after the end of the copolymerization so that a powdercopolymer is obtained, or are exchanged for water so that an aqueousdispersion of the copolymers is obtained.

The copolymers can also preferably be prepared by copolymerizingcomponents (a) and (b) in water. In many cases, it is advisable to carryout the copolymerization in the presence of conventional amounts ofprotective colloids, for example from 0.5 to 5% by weight, orsurfactants in amounts of from 1 to 10% by weight. In some cases, it mayalso be advantageous initially to prepare the water-insoluble polymersof group (b) by a known method in aqueous dispersion and then to add amonomer of the group (a) or a mixture of monomers of group (a). However,the copolymerization of components (a) and (b) can also be carried outby first taking a small amount of a mixture of components (a) and (b) ina polymerization container, initiating the copolymerization by adding aninitiator and then adding components (a) and (b) batchwise orcontinuously in the desired ratio. However, it is also possibleinitially to take the total amount of component (b) and to add themonomers (a) batchwise or continuously. However, the monomers (a) mayalso first be polymerized substantially, ie. by up to 50%, and thepolymers of group (b) added thereafter in order to obtain novelcopolymers.

The copolymerization is carried out in the presence of initiators whichform free radicals under the polymerization conditions. Suitable freeradical initiators are all conventional peroxy and azo compounds, forexample peroxides, hydroperoxides and peroxyesters, such as hydrogenperoxide, dibenzoyl peroxide, di-tert-butyl peroxide, tert-butylhydroperoxide, tert-butyl perpivalate and tert-butylperoxy-2-ethylhexanoate, and azo compounds, for example2,2'-azobis(2-amidinopropane) dihydrochloride,2,2'-azobis(2-methylbutyronitrile) and2,2'-azobis[2-(2-imidazolin-2-yl)-propane]dihydrochloride. It is ofcourse also possible to use initiator mixtures or the known redoxinitiators. The polymerization temperature is preferably from 60° to100° C. Polymerization can of course also be effected outside thistemperature range, the polymerization also being carried out at highertemperatures, for example from 120° to 140° C., in pressure-tightapparatuses. The initiators are used in conventional amounts, forexample from 0.2 to 5% by weight, based on the monomers to bepolymerized.

The novel copolymers can be freed from undesirable impurities by furtherprocess steps, such as steam treatment or partially distilling off thesolvent used together with other volatile components. They may besubjected to further physical treatment steps, such as drying,filtration or dispersing processes.

The novel copolymers have K values of from 10 to 350, preferably from 12to 90 (determined according to H. Fikentscher in 1% strength solution inethanol or N-methylpyrrolidone at 25° C. and pH 7). In cases where thecompounds of component (b) have crosslinked structures, for example inthe case of polybutadiene dispersions or certain polyesters, a K valuedetermination is not possible. The molecular weights in such cases areabove 200,000.

Copolymers of 1-vinylpyrrolidone and styrene are known. They are usuallyprepared by copolymerizing vinylpyrrolidone and styrene. Copolymers ofvinylpyrrolidone and styrene which are suitable for the desiredapplication are also obtainable by grafting 1-vinylpyrrolidone onto ahomopolymer of styrene or grafting styrene onto a homopolymer of1-vinylpyrrolidone. As in the free radical copolymerization of styreneand 1-vinylpyrrolidone, this gives copolymers having block structureswhich contain blocks of polymerized styrene and 1-vinylpyrrolidone.

The copolymers described above and comprising the components (a) and (b)and the copolymers of 1-vinylpyrrolidone and styrene are used asadditives for detergents, for inhibiting dye transfer during the washprocess. The detergents may be in the form of a powder or a liquidformulation. The compositions of the detergent and cleaning agentformulations may be very different. Detergent and cleaning agentformulations usually contain from 2 to 50% by weight of surfactants and,if required, builders. These data apply to both liquid and powderdetergents. Detergent and cleaning agent formulations which are commonlyused in Europe, in the USA and in Japan are tabulated, for example, inChemical and Engn. News 67 (1989), 35. Further information on thecomposition of detergents and cleaning agents appear in WO-A-90/13581and Ullmanns Encyklopadie der technischen Chemie, Verlag Chemie,Weinheim 1983, 4th Edition, pages 63-160. The detergents can, ifrequired, also contain bleach, for example sodium perborate, which, whenused, may be present in the detergent formulation in amounts of up to30% by weight. The detergents and cleaning agents can, if required,contain further conventional additives, for example complexing agents,turbidity agents, optical brighteners, enzymes, perfume oils, other dyetransfer inhibitors, antiredeposition agents and/or bleach activators.

Detergents based on surfactants and, if desired, builders and otherconventional components contain the novel copolymers of the components(a) and (b) or copolymers of

(a) from 20 to 95% by weight of 1-vinylpyrrolidone or a mixture of1-vinylpyrrolidone with up to 20% by weight of other monoethylenicallyunsaturated monomers and

(b) from 5 to 80% by weight of styrene in amounts of from 0.1 to 10,preferably from 0.25 to 5, % by weight.

The copolymers act as dye transfer inhibitors in the washing of coloredand white textiles.

In the Examples which follow, percentages are by weight. The K valueswere determined according to H. Fikentscher, Cellulosechemie 13(1932),58-64 and 71-74, in 1% strength solution in ethanol (Examples 8 and 9and copolymers 3 and 4 in 1% strength solution in N-methylpyrrolidone)at 25° C. in each case and at a pH of 7 in each case.

EXAMPLES

The following polymers were used as component (b):

Polymer (b) No. 1

Methacryloyl-terminated polydimethylsiloxane having an average molecularweight (M_(w)) of 5,000, commercial product from Toa Gosei Chem. Ind.,Japan, under the name Makromonomer AK5.

Polymer (b) No. 2

Polydimethylsiloxane carrying 1.9 mol % of (mercaptopropyl)methyl groupsand having a kinematic viscosity of 150 ctsk (determined at 20° C.Ubbelohde viscometer), commercial product from ABCR GmbH, Germany, withthe name PS 849.

Polymer (b) No. 3

Methacryloyl-terminated condensate of bisphenol A and epichlorohydrin ina molar ratio of 1:1, having a molecular weight (M_(w)) of 1,000,bisphenol A/vinyl ester resin from BASF Aktiengesellschaft, Germany,with the trade name Palatal A 431-01.

Polymer (b) No. 4

Linear polybutadiene having an average molecular weight (M_(w)) of1,800.

Polymer (b) No. 5

Polycondensate of adipic acid/itaconic acid/ethylene glycol in a molarratio of 9: 1: 10, having an average molecular weight (M_(w)) of 2,000.Polymer (b) No. 6

Bis(mercapto)-terminated polytetrahydrofuran having an average molecularweight (M_(w)) of 1,200.

EXAMPLE 1

70 g of ethanol were initially taken in a 1,000 ml flask equipped with astirrer and an apparatus for working under nitrogen and were heated to78° C. under a nitrogen atmosphere. As soon as this temperature wasreached, a feed comprising 40 g of ethanol, 90 g of 1-vinylpyrrolidoneand 10 g of polymer (b) No. 1 was added dropwise in the course of 2hours and a further feed comprising 40 g of ethanol and 1 g of dimethyl2,2'azobisisobutyrate was added dropwise in the course of 4 hours. Afterthe addition of the polymerization initiator, the reaction mixture wasstirred for a further 3 hours at 78° C. and then subjected to steamdistillation. A cloudy solution having a solids content of 47% wasobtained. The K value of the polymer was 52.

EXAMPLE 2

Example 1 was repeated, with the only exception that 10 g of polymer (b)No. 2 were now used instead of polymer (b) No. 1. A cloudy solutionhaving a solids content of 25% was obtained. The polymer had a K valueof 41.

EXAMPLE 3

Example 1 was repeated, with the only exception that 10 g of polymer (b)No. 3 were now used instead of polymer (b) No. 1. A cloudy solutionhaving a solids content of 40% was obtained. The copolymer had a K valueof 57.

EXAMPLE 4

Example 1 was repeated, with the exception that 70 g of 1-vinylimidazolewere now used instead of vinylpyrrolidone and 30 g of polymer (b) No. 4were now used instead of polymer (b) No. 1. A white polymer dispersionhaving a solids content of 27% was obtained. The copolymer had a K valueof 53.

EXAMPLE 5

Example 1 was repeated, with the exception that 33 g of1-vinylpyrrolidone and 67 g of polymer (b) No. 4 were now used. A whitepolymer dispersion having a solids content of 64% was obtained. Thecopolymer had a K value of 37.

EXAMPLE 6

Example 1 was repeated, but 70 g of 1-vinylpyrrolidone and 30 g ofpolymer (b) No. 5 were used. A white polymer dispersion having a solidscontent of 62% was obtained. The copolymer had a K value of 57.

EXAMPLE 7

73 g of 1-vinylpyrrolidone, 90 g of 70% aqueous isopropanol and 8 g ofpolymer (b) No. 6 were initially taken in a 1,000 ml flask equipped witha stirrer and an apparatus for working under nitrogen and were heated to55° C. under a nitrogen atmosphere. As soon as this temperature wasreached, 1.5 g of 2,2'-azobis(N,N'-dimethyleneisobutyramide)dihydrochloride in 20 ml of water were added. After the addition of theinitiator, the polymerization mixture was stirred for 140 minutes at 55°C. Thereafter, a further 0.3 g of the initiator in 10 ml of water wasadded and the reaction mixture was stirred for a further 180 minutes at55° C. and then subjected to steam distillation. An opaque solutionhaving a solids content of 19% was obtained. The K value of the polymerwas 33.

Preparation of known copolymers of vinylpyrrolidone and styrene

Copolymer 1

80 g of 1-vinylpyrrolidone and 20 g of styrene were polymerized by themethod stated in Example 1. An aqueous dispersion having a solidscontent of 28% was obtained. The copolymer had a K value of 66.

Copolymer 2

70 g of 1-vinylpyrrolidone, 20 g of styrene and 10 g of3-methyl-1-vinylimidazolium chloride were polymerized by the methodstated in Example 1. An aqueous polymer dispersion having a solidscontent of 43% was obtained. The copolymer had a K value of 30.

Comparative Example 1

Preparation of a random copolymer of 1-vinylpyrrolidone and ethylacrylate

70 g of ethanol were initially taken in the apparatus described inExample 1 and heated to 78° C. in a stream of nitrogen. After thistemperature was reached, a feed comprising 40 g of ethanol, 60 g of1-vinylpyrrolidone and 40 g of ethyl acrylate was added dropwise in thecourse of 2 hours and a further feed comprising 40 g of ethanol and 1 gof dimethyl 2,2'-azobisisobutyrate was added dropwise in the course of 4hours. The reaction mixture was stirred for a further 3 hours after theend of the addition of the initiator at 78° C. and then subjected tosteam distillation. A white polymer dispersion having a solids contentof 47% was obtained. The copolymer had a K value of 47.

Copolymer 3

200 g of demineralized water, 100 g of 1-vinylpyrrolidone, 2 g ofpolyvinylpyrrolidone having a K value of 30 and 3 g of emulsifier 1(ester of sulfuric acid with an adduct of 2 mol of ethylene oxide with 1mol of lauryl alcohol, was neutralized with sodium hydroxide solution)were heated to 75° C. under a nitrogen atmosphere in a flask equippedwith a stirrer and an apparatus for working under nitrogen. After thistemperature was reached, a feed comprising a mixture of 100 g ofstyrene, 100 g of water and 7 g of emulsifier 1 was added dropwise inthe course of 3 hours and at the same time a further feed comprising asolution of 2 g of sodium persulfate in 50 g of water was added dropwisein the course of 5 hours. After the feed had been added for 1 hour, thereaction temperature increased to 95° C. and the reaction mixture wasstirred for a further 8 hours altogether at this temperature and thensubjected to steam distillation for 2 hours. A dispersion having asolids content of 26% was obtained. The copolymer had a K value of 47.

Copolymer 4

325 g of demineralized water, 30 g of polyvinylpyrrolidone having a Kvalue of 30, 85 g of styrene, 1.25 g of emulsifier 1, 1 g of emulsifier2 (adduct of 11 mol of ethylene oxide with 1 mol of a C₁₃ /C₁₅ fattyalcohol) and 0.5 g of potassium peroxodisulfate were initially taken inthe apparatus described in Example 8 and stirred under a nitrogenatmosphere for 2 hours at 80° C. Thereafter, 4.5 g of emulsifier 2 wereadded and then a mixture of 45 g of styrene and 45 g of1-vinylpyrrolidone and a solution of 0.5 g of potassium peroxodisulfatein 20 g of water were added simultaneously in the course of 2 hours. Thereaction mixture was stirred for a further 2 hours at 80° C. and thenfiltered through a linen cloth. A white dispersion having a solidscontent of 36% and a mean particle diameter of 134 nm was obtained.

EXAMPLE 8

In an apparatus provided with a stirrer and for working under nitrogen,150 g of demineralized water, 5 g of 1-vinylpyrrolidone and 50 mg of2,2'-azobis(amidinopropane) dihydrochloride were added to 125 g of apolybutadiene dispersion having a solids content of 40% and a meanparticle size of 90 nm, according to DE-C-24 27 960, and the mixture washeated to 65° C. under a nitrogen atmosphere. At this temperature, 45 gof 1-vinylpyrrolidone were then added dropwise in the course of 1.5hours and at the same time 1 g of 2,2'-azobis(amidinopropane)dihydrochloride in 30 ml of water was added dropwise in the course of 2hours. After a total of 3 hours after the beginning of the feeds, thetemperature of the reaction mixture was increased to 70° C. for 2 hours.The reaction mixture was then subjected to steam distillation for 2hours. A white dispersion having a solids content of 24% was obtained.The copolymer had a K value of 53.

EXAMPLE 9

110 g of a butadiene/styrene dispersion stabilized with 4 g of potassiumoleate and having a butadiene/ styrene ratio of 3 : 1, a solids contentof 47% and a mean particle size of 70 mm and 5 g of 1-vinylpyrrolidonewere initially taken in the apparatus stated in Example 10 and wereheated to 70° C. under a nitrogen atmosphere. As soon as the reactionmixture had reached this temperature, 45 g of 1-vinylpyrrolidone and 50ml of water were added in the course of 2 hours and, separately fromthis, a solution of 1 g of 2,2'-azobis(amidinopropane) dihydrochloridein 30 ml of water was added in the course of 3 hours. The reactionmixture was stirred for a further 3 hours at 70° C. after the end of theaddition of the initiator and then subjected to steam distillation. Awhite dispersion having a solids content of 17% was obtained. Thecopolymer had a K value of 44. Adsorption test

The adsorption behavior of the polymers stated in Table 1 on activatedsludge from a biological wastewater treatment plant is tested. Thepolymer is dissolved in each case in an aqueous activated sludgesuspension. The concentration of the polymer is at least 100 mg/1, basedon the dissolved organic carbon (DOC). The activated sludgeconcentration is 1 g/l, based on the dry weight. After 48 hours, the DOCis measured in the supernatant solution after the sludge has settledout. Fine activated sludge particles are removed before the DOCmeasurement. ##EQU1##

The following results were obtained:

                  TABLE 1                                                         ______________________________________                                        Polymer prepared according to Example                                                               Degree of elimination                                   ______________________________________                                        4                     53                                                      Copolymer 1           37                                                      8                     59                                                      9                     41                                                      Polyvinylpyrrolidone (K value 30)                                                                   <5                                                      ______________________________________                                    

The Examples show that the novel polymers exhibit substantially improvedelimination behavior in sewage sludge than polyvinylpyrrolidone.

Use Examples

Washing tests

To test the efficiency, white test fabric was washed together withcolored textile samples of cotton in a launderometer. The dye transferwhich occurred was measured photometrically. The particular depths ofcolor were determined from the reflectance values measured on theindividual test fabrics, and the efficiency of the polymers can bederived from the said depths of color. An efficiency of 100% means thatthe test fabric retained its original depth of color, ie. it was notcolored. An efficiency of 0% is determined in the case of a test fabricwhich has the same depth of color as a test cloth which was washedwithout the addition of a dye transfer-inhibiting additive.

The textile samples were colored with the following dyes:

C.I. Direct Black 51 (constitution number 27720), C.I.

Direct Blue 218 (24401), C.I. Direct Red 79 (29065), C.I.

Direct Black 22 (35435), C.I. Direct Blue 71 (34140),

C.I. Reactive Black 5 (20505).

    ______________________________________                                        Washing conditions                                                            Washing apparatus  Launderometer                                              Wash cycles        1                                                          Temperature        60° C.                                              Duration of washing                                                                              30 min                                                     Water hardness     3 mmol Ca.sup.2+, Mg.sup.2+ (4:1)/1                        Test fabric        Cotton                                                     Liquor ratio       1:50                                                       Amount of liquor   250 ml                                                     Detergent concentration                                                                          7.0 g/l                                                    Detergent composition [%]                                                     Zeolite A          20                                                         Sodium carbonate   11                                                         Dodecylbenzenesulfonate                                                                          5                                                          Soap               1.3                                                        C.sub.13 /C.sub.15 oxo alcohol × 7                                                         3.9                                                        ethylene oxide units                                                          Acrylic acid/maleic acid copolymer                                                               2.7                                                        70/30, Na salt, MW = 70,000                                                   Sodium carboxymethylcellulose                                                                    0.4                                                        Water              7.0                                                        Polymer according to Table 2                                                                     1.0                                                        Sodium sulfate     to 100                                                     ______________________________________                                    

                                      TABLE 2                                     __________________________________________________________________________    Polymer prepared                                                              according to                        Copolymer   Comparative                   Example: 1  2  3  4  5  6  7  8  9  1  2  3  4  Example                       __________________________________________________________________________                                                    1                             Direct   31.1                                                                             30.4                                                                             33.7                                                                             32.8                                                                             26.2                                                                             24.9                                                                             35.7                                                                             27.7                                                                             30.1                                                                             25.7                                                                             29.3                                                                             26.5                                                                             25.8                                                                             10.8                          Black 51                                                                      Direct Blue                                                                            29.4                                                                             34.4                                                                             30.5                                                                             89.0                                                                             23.2                                                                             34.8                                                                             38.2                                                                             32.0                                                                             22.7                                                                             18.5                                                                             31.2                                                                             24.2                                                                             28.9                                                                             10.8                          218                                                                           Direct   78.8                                                                             84.0                                                                             80.6                                                                             85.2                                                                             71.8                                                                             73.3                                                                             82.2                                                                             78.6                                                                             68.2                                                                             69.6                                                                             70.3                                                                             69.3                                                                             64.1                                                                             31.2                          Red 79                                                                        Direct   76.6                                                                             79.3                                                                             81.0                                                                             80.9                                                                             74.3                                                                             71.1                                                                             82.3                                                                             73.4                                                                             71.1                                                                             79.5                                                                             78.4                                                                             75.8                                                                             68.6                                                                             27.8                          Black 22                                                                      Direct Blue                                                                            96.9                                                                             97.2                                                                             97.1                                                                             97.5                                                                             90.7                                                                             91.7                                                                             97.6                                                                             96.1                                                                             91.9                                                                             93.8                                                                             92.7                                                                             91.2                                                                             91.7                                                                             43.6                          71                                                                            __________________________________________________________________________

The results in Table 2 show that the novel polymers have substantiallyhigher efficiency than comparable polymers having a similar proportionof a less water-soluble component, for example Comparative Example 1.

We claim:
 1. A copolymer which is obtainable by free radicalcopolymerization of a mixture of(a) from 20 to 95% by weight of a1-vinylimidazole of the formula (I) ##STR4## where R is H, CH₃ or C₂ H₅and n is from 1 to 3, or a mixture of 1-vinylimidazoles of the formula Iwhich contains up to 20% by weight of other monoethylenicallyunsaturated monomers, and (b) from 5 to 80% by weight of water-insolublepolymers selected from the group consisting of unsaturated polyesters;homopolymers of butadiene; copolymers of butadiene with styrene,acrylonitrile, acrylates of alcohols of 1 to 8 carbon atoms, isoprene,vinyl ethers where the alkyl chain is of 1 to 18 carbon atoms andacrylic acid; mercaptoalkyl-carrying polysiloxanes; andbis(thiol)polytetrahydrofurans.
 2. A process for the preparation of acopolymer as claimed in claim 1, which comprises copolymerizing(a) from20 to 95% by weight of a 1-vinylimidazole of the formula I, a mixture ofr a 1-vinylimidazole which contains up to 20% by weight of othermonoethylenically unsaturated monomers and (b) from 5 to 80% by weightof water-insoluble polymers selected from the group consisting ofunsaturated polyesters, homopolymers of butadiene, copolymers ofbutadiene with styrene, acrylonitrile, acrylates of alcohols of 1 to 8carbon atoms, isoprene, vinyl ethers where the alkyl chain is of 1 to 18carbon atoms and acrylic acid; mercaptoalkyl-carrying polysiloxanes andbis(thiol)polytetrahydrofuransin water, an alcohol, an ester or aketone, each having a boiling point below 135° C., or a mixture of thestated solvents, in the presence of free radical initiators and in thepresence or absence of protective colloids and surfactants.
 3. Adetergent comprising surfactants, builders, and other conventionalcomponents, which contains from 0.1 to 10% by weight of a copolymerprepared by free radical copolymerization of a mixture of(a) from 20 to95% by weight of 1-vinylpyrrolidone, a 1-vinylimidazole of the formula(I) ##STR5## where R is H, CH₃ or C₂ H₅ and n is from 1 to 3, a mixturethereof or a mixture of 1-vinylpyrrolidone or 1-vinylimidazoles of theformula I which contains up to 20% by weight of other monoethylenicallyunsaturated monomers, and (b) from 5 to 80% by weight of water-insolublepolymers selected from the group consisting of unsaturated polyesters;homopolymers of butadiene; copolymers of butadiene with styrene,acrylonitrile, acrylates of alcohols of 1 to 8 carbon atoms, isoprene,vinyl ethers where the alkyl chain is of 1 to 18 carbon atoms andacrylic acid; mercaptoalkyl-carrying polysiloxanes; and bis (thiol)polytetrahydrofurans, which contain at least one ethylenicallyunsaturated double bond or one mercapto group in the molecule.